I had previously felt an improvement in my concentration and length of time thinking prior to mental fatigue with the B12 cyanocobalamin (swallowed) whereas the under the tongue B12 mecobalamin doesn't seem to have the same effect.

My research hasn't found anything compelling regarding the ingestion by either swallowing or under the tongue. Does anyone else have a similar experience?

Maybe I have to wait a while to "load" due to the change in the type of B12?